Did Kate Middleton Just Drop a Major Hint That She's Ready for Baby No. 4?

Kate Middleton has officially caught a case of royal baby fever. The 37-year-old mother of three began a second day of engagements in Northern Ireland on Thursday by greeting well-wishers, and she may have let slip that she's ready for baby no. 4.

One of the fans who was lucky enough to meet the Duchess of Cambridge was 5-month-old baby James Barr and his father, Alan Barr.

She then greeted baby James, telling him: “You’re a very sweet little boy.”

Then, Middleton reportedly told Barr, “He’s gorgeous. It makes me feel broody.” Barr, ever the inquisitor, then asked Kate the question on everyone’s lips: “Baby number four?” Middleton responded with a laugh, telling the new dad, “I think William would be a little worried.”

Kate and Wills are already parents to an adorable brood which includes Prince George, 5, Princess Charlotte, 3, and Prince Louis, 10 months.

And while on tour with William, Kate's children weren't far from her mind as she greeted well-wishers in Ballymena. She told one little girl in a pink coat: “I love your cool coat. Charlotte loves pink.”

The Duke and Duchess of Cambridge are pleased to share a new photograph of their family. The photograph, taken by Matt Porteous, shows The Duke and Duchess with their three children at Anmer Hall. This photograph features on Their Royal Highnesses' Christmas card this year.

WATCH: Kate Middleton Is Giving Us Mermaid Vibes in This Glittering Gown.